Figure 3. IL-8 induction capacity of site-directed short deletion mutants in CagL in comparison to the parental strain H. pylori SU2.

AGS cells were infected for 22 h (MOI = 50) with several isogenic chromosomal HP0539/cagL mutants as indicated in the figure. Culture supernatants of coincubated AGS cells were tested for IL-8 by ELISA. The level of IL-8 secretion induced by contact with the SU2 reference strain was set to 100%. The corresponding values of the HP0539/cagL motif mutants are depicted in percent in relation to wild-type levels. Results from two independently generated and validated clones are depicted for each motif deletion mutant. The data shown are results (mean and SD) from triplicate measurements of at least four independent experiments. Significance of differences in comparison to the parental strain was calculated by student’s t-test shown as black asterisks above each bar: ***p < 0.01; **p < 0.02; *p < 0.05. The plus and minus signs at the right side of the figure indicate: [++] normal to slight reduction, [+] clear reduction, and [−] strong reduction.